Sigma Orionis

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Multiple star
σ Orionis
Sigma Orionis.JPG
DSS image
AladinLite
Observation
dates equinoxJ2000.0 , epoch : J2000.0
Constellation Orion
Right ascension 05 h 38 m 44.8 s
declination -2 ° 36 ′ 0 ″
Apparent brightness A: 4.2 likes
B: 5.1 likes
C: 8.79 likes
D: 6.62 likes
E: 6.66 likes
Typing
B − V color index A  :? B  :? C:  −0.02
D:  −0.20 E:  −0.18 
U − B color index A  :? B  :? C:  -0.25
D:  -0.87 E:  -0.86 
Spectral class A: O9V
B: B0.5V
C: A2V
D: B2V
E: B2Vp
Variable star type Component E 
Astrometry
distance ≈ 1060  ly
Physical Properties
Other names
and catalog entries
Bayer name σ Orionis
Flamsteed name 48 Orionis
Bonn survey BD −2 ° 1326, −2 ° 1327
Bright Star Catalog HR 1931, 1932
Henry Draper Catalog HD 37468, 37479
Hipparcos catalog HIP 26549, 26551
SAO catalog SAO 132406, 132408
Tycho catalog TYC 4771-1196-1,
4771-1195-1,
4771-1194-1 [1]Template: Infobox star / maintenance / specification of the TYC catalog
Other names ADS 4241 • Σ 762
AB: β 1032
E: V1030 Orionis

Sigma Orionis ( σ Orionis , short σ Ori ) is a system of five stars in the constellation Orion, about 1060 light years away . The core is a spectroscopic double star with magnitudes 4.2 and 5.1 mag, the sum of which is 3.8 mag. The star group is part of the eponymous Sigma-Orionis cluster .

Star system

In the center of Sigma Orionis lies a stable binary star system with Sigma Orionis A and Sigma Orionis B , around which the three outer stars Sigma Orionis C , Sigma Orionis D and Sigma Orionis E move on irregular orbits . A and B are only 0.25 arcsecond apart and can therefore hardly be separated even in large telescopes.

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